Toggle drawing press



Oct. 1, 1929. V R. B. TREER 1,729,658

TOGGLE DRAWING PRESS Filed Aug. 3, 1927 2 Sheets-Sheet 1 FIG. 1

' INVENTOR, R 02. 75M,

ATTORNEY Patented Oct. 1, 192 9 PATENT OFFICE ROSS B. TREER, OF TOLEDO, OHIO TOGGLE DRAWING PRESS Application filed August 3, 1927. Serial No. 210,427.

This invention relates to new and useful improvements in toggle drawing presses.

It is the principal object of my invention to provide a toggle drawing press in which the blank-holder is operated from the plunger to leave the ends and center of the crankshaft clear.

It is another object of my invention to provide a blank-holder which is toggle-operated by the plunger and which may be employed in a single or multiple crank press.

Other important and incidental objects will be brought out in the following specification and particularly set forth in the subjoined claims.

In the accompanying drawings, Figure 1 is a side elevational view of my improved drawing press. Figure 2 is an end vertical sectional view taken through the same, showing 0 the plunger and blank-holder in their raised positions. And Figure 3 is a vertical sectional view taken through said press, showing the blank-holder and contained plunger in their down positions.

Referring to the accompanying drawings for a detailed description of my invention, the numeral 1 designates a bed for my press and 2 a frame therefor having side uprights 3 and the top or crown portion 4.

Guided for vertical movement between the uprights 3 is a blank-holder 5 through which works a plunger 6 for the shaping die, as is well understood in the art.

The usual crank shaft 7 of the press is journaled in bearings 8 in the uprights 3, and is disposed in the center vertical plane of the blank-holder and plunger. The crank shaft is provided with cranks 9 which are connected bypitmen 10 to the plunger 6.

For the purpose of operating the blank holder 5 from the plunger 6 rather than from the crank-shaft 7, thereby to leave the ends and center of the latter clear, I provide the following toggle mechanism for operatively connecting the blank-holder to the plunger.

Pivotally connected to screw members 11 in the flanged lower end 12 of the crown 4 are links 13 pivotally secured at their lower ends to bell-crank levers 14. Each lever 14 is pivotally secured by a screw 15 to a double side wing 16 on the blank-holder 5. The free ends of the bell-crank levers 14 are connected by links 17 to bell-crank levers 18 pivotally secured by screws 19 to the wings 16.

The lower ends of the bell-crank levers 18 are connected by links 20 to links 21 that are in turn connected by links 22 to links 23. The latter links which with the links 22 project through slots 24: in the blankholder, are pivotally secured to the plunger 6.

It will now be seen that when the plunger 6 is forced downwardly by the crank shaft 7, it will, through the toggle and link mechanism just described, draw the blank-holder 5 down quickly to a position in advance of the plunger, where it dwells to hold the blank during the remainder of the downward stroke of the plunger. After the plunger has co1npleted its drawing stroke, it will raise the blank-holder to the position shown in Figure 2 through the same toggle and link mechanlsm.

It is thus seen that the blank-holder derives its power from the plunger. The toggle and link mechanism connecting it to the plunger leaves the ends of the crank shaft clear and does not interfere with other attachments that are sometimes necessary and difiicult to apply to large presses. It also may be applied to a single or multiple crank press.

I do not wish to be limited to the details of construction and arrangement herein shown and described, and any changes or modifications may be made therein within the scope of the subjoined claims.

Having described my invention, I claim:

1. A drawing press comprising a frame having a crown, a blank-holder reciprocable in said frame, a plunger movable inside said blank-holder, a crank shaft, a connection between the latter and the plunger to reciprocate it in the blank-holder, the latter formed with slots, side wings on said blankholder, a link and toggle connection through said slots between the plunger and the side wings of said blank-holder, and flexible means connecting the latter with said crown.

2. A drawing press comprising a frame having a crown, a blank-holder reciprocable in said frame, a plunger movable inside said blank-holder, a crank shaft, a connection between the latter and the plunger to reciprocate it in the blank-holder, the latter formed with slots, side wings on said blank-holder, bell crank levers on said wings, a link connection through said slots, between the plunger and said bell crank levers, a second bell crank lever secured to each wing, a link connection between the bell crank levers on each wing, and a link connecting the second bell crank lever of each wing with said crown for the purpose specified.

In testimony whereof I have hereunto setlny hand this 29th day of July, 1927.

' ROSS B. TREER. 

